关于javamail 邮件附件内容（是内容不是附件名）乱码的有关问题

public byte[] uploadFile(String fileName){    // 上传附件
        FileConnection fc = null ;
        byte[] b = null ;
        DataInputStream dis = null ;
        String selectedFilePath ;
        
        try {    // 此处要添加路径
            fc = (FileConnection) Connector.open(HOME_PATH+currPath + fileName);
            selectedFilePath = HOME_PATH + currPath + fileName ;
            if(!fc.exists()){
                return null;
            }
    //========================此处是读取文件的代码===========================//    
            b = new byte[(int)fc.fileSize()];
            dis = fc.openDataInputStream();
            dis.read(b);    // 将文件以字节的形式写入到字节数组里
            dis.close();
            if(fc != null){
                fc.close();
            }
    //=================================================================//
            PhoneMailMIDlet.EMAILMESSAGE.setHasFile(true);
            PhoneMailMIDlet.EMAILMESSAGE.setFileName(fileName);
            PhoneMailMIDlet.EMAILMESSAGE.setFilePath(selectedFilePath);
            PhoneMailMIDlet.CTB_SCREEN.insert("(含附件)",0);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return b ;
    }

DataInputStream dis=new DataInputStream(req.getInputStream());
        from = dis.readUTF();
        hostName = dis.readUTF();
        password = dis.readUTF() ;
        receiver = dis.readUTF();
        subject = dis.readUTF();
        content = dis.readUTF();
        hasFile = dis.readBoolean();
        if(hasFile){
    //===========================读取客户端发过来附件的信息========================//
            fileName = dis.readUTF();    //附件名
            fileSize = dis.readInt();    // 附件的字节大小
            fileByte = new byte[fileSize];    // 生成保存读取附件的字节数组，大小为附件大小
            dis.read(fileByte);    // 获取文件的字节编码 
            System.out.println("附件的大小："+fileByte.length);
    //=========================================================================//
        }
        System.out.println("\n\n\n");
        System.out.println("from:"+from);
        System.out.println("Host Name:"+hostName);
        System.out.println("receiver:"+receiver);
        System.out.println("subject:"+subject);
        System.out.println("content:"+content);
        System.out.println("file name :"+fileName);
        System.out.println("\n\n\n\n");
  
                       ……
                       ……
public File byteToFile(byte[] b){
        File attchFile = new File(fileName);
        try {
    //====================下是将读取的附件字节流转换成文件形式===========================//
            FileOutputStream fos = new FileOutputStream(attchFile);
//            DataOutputStream dos = new DataOutputStream(fos);
            fos.write(b);
            fos.close();
            fos.close();
    //==============================================================================//
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("byte to file 出错....");
        }
        return attchFile;
    }